Nonhalation film



Oct 3, 1933. A. NARATH 1,929,254

NONHALATION FILM Filed Nov. l2, 1930 Raus/lema Anp' Carl/fao w/TH anneau Powpmv y Inventor:

Alber't: Norodch, bLJ MM His Aobo'rvneg.

Patented Oct. 3,` 1933 NONHALATION FILM Albert Narath, Berlin, Germany, assigner to General Electric Company, a corporation o! New York Application November 12, 1930, serial' No.

Germany 495,251, and in 4 Claims.

My invention relates to photographic ilms such for example as those employed in making motion picture records, sound records and sound-picture records. It is well known to those skilled in the art that when a film is exposed to a strong light in the recording process, objectionable halation effects often are produced. This is particularly true in sound recording where the exposure of the lm is elected by a l0 narrow beam of light of great intensity. It is the object o! my invention to provide an improved process and product whereby the above mentioned objectionable halation effects may be greatly reduced if not entirely eliminated.

In accordance with my invention I bring about the desired result by roughening the rear face o1 the lm so that light which passes through the emulsion in the exposing process is not reflected back into the emulsion as with films constructed in the usual manner,V but is dill'used or dispersed. The roughening of the nlm max-:be done. in any suitable manner and either before or after the emulsion is applied thereto. surface alight absorbing substance which lllls in all of the depressions or interstices produced by the roughening process.` It is desirable that the light absorbing substance employed shall be one having the same or approximately the same 0 refractive index as the material composing the body of the ilm. It is also desirable that the substance be of such a nature that it is readily removed during the developing, the xing or the washlngof the nlm. While various substances may be used for this purpose, I.have found carbon powder to be satisfactory.

In the single-ligure of the drawing illustrat- I .also apply to the roughened1 lm November 16, 1929 (c1. 11s-9) ing my invention I have shown at 1 a film having on one 4side the usual light sensitive emulsion 2. The rear face of the lm is roughened and 'covered with a light absorbing substance 3 such for example as carbon powder. With a o lm` as so constructed, that'part of the exposing light .which passes-on through the emulsion and thebody of the lm is electively dilused, or dispersed by the roughened rear face and is absorbed by the absorbing material thereon. '55

I have chosen the particular embodiment described above as illustrative of my invention and -it will be apparent that various other modications may be made without departing from the spirit and scope of myinvention, which modications I aim to cover by the appended claims.

`What I claim as new and desire to secure by Letters Patent-of the United States is:

f1. T he method of reducing halation in a-photographic-film which comprises roughening the material forming the film at the rear face thereof and applying to. the roughened face a light absorbing substance.4

v2. The method of reducing halation ina photographic iilm which comprises roughening the material forming the lm at the rear face thereof and applying carbon powder to the roughened tace. l

3. A non-halativellm having the material of which thelm is` composed roughened at the rear face thereof and covered with a light absorbing substance.

4. A non-halative film having the material of whichv the lm is composed.v roughened at the rear face thereof and covered with a light absorbing substance comprising carbon powder.

. ALBERT NARATH. 

